644120617 has 8 divisors (see below), whose sum is σ = 736848000. Its totient is φ = 551570784.

The previous prime is 644120611. The next prime is 644120621. The reversal of 644120617 is 716021446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644120617 - 2⁷ = 644120489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644120611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36517 + ... + 51202.

It is an arithmetic number, because the mean of its divisors is an integer number (92106000).

Almost surely, 2^644120617 is an apocalyptic number.

It is an amenable number.

644120617 is a deficient number, since it is larger than the sum of its proper divisors (92727383).

644120617 is a wasteful number, since it uses less digits than its factorization.

644120617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88775.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 644120617 is about 25379.5314574560. The cubic root of 644120617 is about 863.6194208804.

The spelling of 644120617 in words is "six hundred forty-four million, one hundred twenty thousand, six hundred seventeen".